Process for making cellulose materials rotproof



United States Patent PROCESS F OR MAKING CELLULOSE MATERIALS ROTPROOFCornelis van Bochove, The Hague, and Hendrik J. Hueck,

Delfgauw, Netherlands, assignors to Nederlandse 0rganisatie voorToegepast-Natuurwetenschappelijk 0nderzoek ten behoeve van Nijverheid,Handel en Verkeer, The Hague, Netherlands No Drawing. Filed June 30,1958, Ser. No. 745,326

Claims priority, application Netherlands July 4, 1957 5 Claims. (Cl.117-1385) It has been found that cellulose materials such as cotton canbe protected against rotting by treating them with chloracetamide andformaldehyde in a molar ratio of 1 mol chloracetamide on not more than 1mol formaldehyde; instead of this the material can also be treated withmethylolchloracetamide.

The effect is specific; only instead of chloracetamide, bromacetamide oriodoacetamide may be used, but for practical purposes this isunnecessarily expensive. With other halogen carboxylic acid amides onedoes not nearly obtain the same effect as with chloracetamide. The sameholds good for the unsubstituted acid amides. The methylol compounds ofthe following materials have been examined for example:

Acetamide Butyramide Capronamide Beta-chloropropionamideDichloracetamide but the effect found, if any, was negligible. Neitherdid a treatment with formaldehyde only, yield a rotproof product.

As it is suflicient for the reaction when one mol of formaldehyde ispresent per mol of chloracetamide, and an excess of formaldehydetherefore not only means a waste but may moreover be detrimental notmore than one mol of formaldehyde should be present per mol of halogenacetamide. By formaldehyde is also meant a material yieldingformaldehyde such as paraldehyde.

The invention will be illustrated with regard to the treatment ofcotton; the protection of cotton against rotting is namely veryimportant and therefore this treatment has been subjected to the mostdetailed examinatron.

The particulars given below are obtained with the following materials:

In impregnating a foulard was used:

Fabric speed: 0.7 m./min.;

Squeezing pressure: 350 kg. across 28 cm. fabric width 65 Squeezingyield: about 60%.

2,938,815 Patented May 31, 1960 lCC The drying and after-heating tookplace following circumstances:

Drying temperature: C.;

Drying time: 10 min.;

Temperature during after-treatment: see below; Time: 4 /2 min.

In order entirely to remove material which might not have reacted, thefoulard was rinsed a few times'with cold water first, and afterwardstwice with water. of 70 C.

The burying tests and the tensile strengths were determined according toinstruction Vitno-Bio Al.

The treatment is carried out as follows by way of example.

The cotton was impregnated with a solution of methylolchloracetamide inwater to which a catalyst was added (e.g. oxalic acid). temperature(130140) followed which lasted a few minutes, and during which thereaction proper took place. After this rinsing was effected.

The cotton treated in this way was subjected to a burying test. After 1,2 and 4 weeks a number of strips was removed and the tensile strengthdetermined. As a criterion for the behaviour in the ground the reststrength was taken. The definition of rest strength is as follows: theratio between the tensile strengths after and before the burying,expressed in percents.

The results of a number of these experiments was as follows:

Table 1.--Results of burying tests of cotton, treated withmethylolchloracetamide under the blank rest strength (percent) Degreetensile after- Test No. of substistrength tution l (kg/25 mm.) 1 week 2weeks lweeks 1 Expressed in the number of side groups per 100 glucoseunits.

From these results it can be concluded that there is an evidentcorrelation between the degree of substitution and the resistanceagainst the influence of micro-organisms. Complete resistance for fourweeks of burial is obtained at a substitution degree of about 6. Whenone week of burial is chosen as a criterion, a substitution degree of lto 2 is sufiicient. These degrees of substitution are extraordinarilylow, as compared to other methods for making cellulose material rotproofby chemical modification, such as acetylating and cyanoethylating, inwhich at least /3 of the total number of OH- groups of the celluloseshould be replaced to ensure success, which, however, implies a drasticchange of the qualities. The effect at the above-mentioned very lowdegrees of substitution is strictly specific of the process according tothe invention.

Besides a burying test a few samples of treated cotton were subjected toa treatment with enzyme solution for two weeks.

After drying a treatment at a higher "chloracetamide respectively inwater.

test.

The results of this can be summarized as follows: Table 2.-Cottontreated with methylolchloracetamide ,For purposes of comparison theresults after 1 weeks burial have been inserted in this table. V

1 In this test too it appeared, that the cotton is made re-' sisteut bythe reaction with methylolchloracetamide. The

results of this test correspond more or less to those of 1 Weeks burial.

As a matter of course'one is neither bound to the above-mentionedspecifications of the fabric, nor to the details of impregnating,.drying and after-treatment.

In order to obtain more certainty about the efiect of the bondedchloracetamide, examination was made, as to what influence looselyapplied chloracetamide had on the resistance of cotton. To this endcotton was impregnated with solutions of chloracetamide and methylol-Both compounds were applied to the fabric in various concentrations,which corresponded more or less to the quantity of bondedchloracetamide.

The impregnated fabrics were subjected to a burying Results: I

Table 3.Comparison of "bonded and loose methylj It is clear that "loose"chloracetamide has hardly any efiect at all.

The influence of the variables in the process according to the inventionwas further examined.

During the reaction of celloluse with methylolchloracetamide thefollowing variables occur:

' (1) Concentration of methylolchloracetamide in the impregnatingliquid;

(2) Nature and quantity of the catalyst used.

(3) Temperature and duration of the after-heating. In this reaction thequantity of bonded chloracetamide is a criterion for the degree ofconversion. Besides that, this kind of reactions requires that themechanical properties of the cotton may not be subject to any orscarcely to any alterations. A criterion for this is V the tensile st einvestigation was now made as to what influence some of theabove-mentioned variables had on the attained degree of substitution andon the loss of tensile strength. (1) Influence of the concentrationofthe methylolchloracetamide. p

A series of tests was carried out, in which a cotton was impregnatedwith solutions of methylolchloracetamide in water with'a content varyingfrom 2 to 20%.

The results are given in Table 4.

Table 4.--Connection between bath concentration and degree ofsubstitution and tensile strength Reaction conditions:

pH of the impregnating bath: 2.5 Catalyst: oxalic acid Drying at 70-80C. After-heating: 5 min. at 140 C.

. .Methylol Degree of Tensile Loss 01 Test No. chloracetsubstistrengthtensile; amide tution, (kg/25 strength, (percent) percent mm percent (2)Influence of nature and quantity of the catalyst used and of thetemperature of after-heating. Oxalic acid was chosen for a catalyst.

With oxalic acid as a catalyst the pH was adjusted to 4.5 and 2.5.Besides this a test was carried out with a pH of 6.5, which was obtainedby adding a few drops of NaOH to a solution of methylolchloracetamide,which in itself had a pH of about 5.5. So here no oxalic acid was added.

The results are given in Table 5.

Table 5.Influence of the pH of the impregnating bath and the reactiontemperature on the degree of substitution Reaction conditions:

Bath concentration 16.7%, V After-heating at and C. respectively for 5minutes.

Tempem- Degree 0! Loss of Test No. pH -ture substltensile 0.) tution,strength,

percent percent From all these tests it is evident, that by thetreatment according to the invention a product is obtained which isextremely rotproof.

Some tests were carried out in order to compare the present process withknown processes.

(l) Influence of repeated washing and dry-cleaning on the rotproofnessof cotton, treated in the following ways:

(a) According to the invention (substitution degree 6;

of. Table I);

(b) Copper naphthenate (approx. 0.7% Cu); (0) Lauryl-pentachlorophenol(+water repellent agent) (approx. 2%).

These three samples were washed 5 times and drycleaned 5 times. Bothtreatments were carried out in a conventional domestic washing machinemanufactured by the Allgemeine Elektrizitats Gesellschaft, a well knownmanufacturing firm of West Germany.

For the washing the washing agent Savonine Compleet was used. SavonineCompleet stands for a detergent of the following composition in percentby weight: common soap 20%; sodium carbonate anhydrous 45%; sodium metasilicate 91-1 0 12%; .sodium salt of carboxy methyl cellulose(NaGMC)...1.2%;..the: rest.wa-

ter. This preparation was applied in a quantity of g./litre. The weightratio of dry sample to bath liquid was 1:20. The washing took place forone quarter of an hour at 80 C. After this rinsing in distilled watertook place twice, each time for 5 minutes, and drying at 60 C.

Dry-cleaning took place in trichloroethylene at 20 C. for 10 minutes.After this drying at the air took place.

After the termination of the washing tests the samples were subjected toa burying test for two and four weeks.

In Table 6 below is indicated what procentual rest strengths the stripshad that had been buried.

From this the following is apparent:

Washing and dry-cleaning have only very little influence on therotproofness of cotton which has been treated according to theinvention.

Cotton treated with copper naphthenate will stand dr cleaning, but doesnot stand washing quite as well.

The etfect of lauryl-pentachlorophenol disappears entirely, both bydry-cleaning and by washing.

These results clearly show the difference between the effect of chemicalreaction with the cellulose according to the invention and the effect ofimpregnating loosely with the usual fungicides.

Some exposition tests were also carried out.

On the roof of a building a comparative test was carried out in a numberof racks, in which a number of cotton strips, which had been treated invarious ways, were exposed to the sunlight. In this test one half of thestrips was put behind frames of Plexiglas, by which the influence of thesunlight was not eliminated, but that of the rain was.

After the termination of the exposition (1, 2, 4 and 8 months) a certainnumber of the strips were subjected to a burying test (2 weeks).

The following treatments were applied:

(a) Treatment according to the invention (degree of substitution 6);

(b) Treatment with copper naphthenate (0.8% Cu);

(c) Treatment with lauryl-pentachlorophenol+Water repellent agent;

(d) Treatment with copper-S-oxyquinoline (0.7% Cu).

In the following Table 7 the rest strengths (in percents of thenon-buried samples) are again given.

From these results it is evident that cotton treated according to theinvention, when exposed to atmospheric influences, is much slower tolose its rot-preventing qualities than cotton which has been impregnatedaccording to the usual processes. This should be ascribed to thechemical reaction which has taken place when treating it withmethylolchloracetamide.

What we claim is:

1. Process for improving the resistance against microbiological attackof cellulose-containing materials by impregnating the material with anaqueous solution of halogeno-acetamide and formaldehyde and an acidcatalyst, the amount of formaldehyde being not greater than one mole permole of halogeno-acetamide, drying the impregnated material andsubjecting it to a temperature References Cited in the file of thispatent UNITED STATES PATENTS 2,270,520 Riehen I an. 20, 1942 2,446,864Abrams Aug. 10, 1948 2,587,957 Bauer et al Mar. 4, 1952 FOREIGN PATENTS495,714 Great Britain Nov. 14, 1938

1. PROCESS OF IMPROVING THE RESISTANCE AGAINST MICROBIOLOGICAL ATTACK OFCELLULOSE-CONTAINING MATERIALS BY IMPREGNATING THE MATERIAL WITH ANAQUEOUS SOLUTION OF HALOGENO-ACETAMIDE AND FORMALDEHYDE AND ACIDCATALYST, THE AMOUNT OF FORMALDEHYDE BEING NOT GREATER THAN ONE MOLE PERMOLE OF HALOGENO-ACETAMIDE, DRYING THE IMPREGNATED MATERIAL ANDSUBJECTING IT TO A TEMPERATURE OF BETWEEN 110 AND 160*C.